The present invention relates generally to management of network resources, and more particularly, to techniques for providing resource-efficient live media streaming to heterogeneous clients.
Events such as sporting games, musical performances, and news reports are often made available via live media streaming. New applications for live media streaming, such as distance learning and tele-surgery, continue to emerge.
Although conventional live media streaming is useful, there exist a number of shortcomings. Currently, methods for live stream delivery have substantial bandwidth requirements. When bandwidth nears or reaches capacity it is common for data to be discarded. This often causes the information received to be of poor quality.
Various techniques for dealing with such problems have been proposed. For example, Zhang et al., “Efficient Selective Frame Discard Algorithms for Stored Video Delivery Across Resource Constrained Networks,” Proceedings of the IEEE INFOCOM Conference, Vol. 2, pp. 472-479, 1999, discloses an optimal frame discard scheme, which minimizes the number of frames to be skipped, for given bandwidth and buffer size. However, this scheme simply discards frames and does not provide any way to replace them.
McCanne et al., “Low-complexity Video Coding for Receiver-driven Layered Multicast,” IEEE Journal on Selected Areas in Communication, 15(6); 983-1001, August 1997, discloses a transport protocol based on RTP (Real Time Protocol), in which clients can subscribe to different layers (each one increasing the quality, but also the rate). The video layers are sent over different multicast groups, and the receiver decides to which groups it wants to subscribe, based on its available bandwidth. However, this scheme can rapidly result in bandwidth overflow at the server and is overly complex and costly to implement.
Other methods include transcoding within intermediate nodes to adapt the stream to the downstream available bandwidth, but such methods pose high computational requirements.